Micro-pulsed plasma thruster having coaxial cable segment propellant modules

Abstract

A single energy storage capacitor is used to apply electrical energy to selected propellant modules, each module generating thrust in a desired direction by the high voltage induced vaporization of the copolymer spacer material in a conventional coaxial cable within the selected module. A lightweight, low cost, and EMI free thruster is thus provided.

What is claimed is:  
     
       1. In a thruster particularly well adopted to control the attitude of a small space satellite the improvement comprising: 
       (a) at least one coaxial cable segment having an inner conductor and an outer conductive shell positioned about said inner conductor, together with spacer material positioned between said inner conductor and said outer conductive shell, which material can readily vaporize upon the application of a high voltage pulse applied thereto; and  
       (b) thruster control means for applying said high voltage pulse across said spacer material.  
     
     
       2. The thruster of claim  1  wherein said spacer material comprises a tetrafluroethylene polymer. 
     
     
       3. The thruster of claim  1  wherein said high voltage pulse has a voltage of at least 1000 volts. 
     
     
       4. The thruster of claim  2  wherein said high voltage pulse has a voltage of at least 1000 volts. 
     
     
       5. In a thruster particularly well adopted to control the attitude of a small space satellite the improvement comprising: 
       (a) a plurality of propellant modules, each module comprising a coaxial cable segment having an inner conductor and an outer conductive shell positioned about said inner conductor together with spacer material positioned between said inner conductor, and said outer conductive shell, which material can readily vaporize upon the application of a high voltage pulse applied thereto; and  
       (b) a single thruster control means for selectively applying said high voltage pulse across spacer material of coaxial cable segments of selected ones of said modules.  
     
     
       6. The thruster of claim  5  wherein said spacer material comprises a tetrafluroethylene polymer. 
     
     
       7. The thruster of claim  5  wherein said high voltage pulse has a voltage of at least 1000 volts. 
     
     
       8. The thruster of claim  6  wherein said high voltage pulse has a voltage of at least 1000 volts. 
     
     
       9. The thruster of claim  5  wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       10. The thruster of claim  6  wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       11. The thruster of claim  7  wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       12. The thruster of claim  8  wherein said thruster control means includes an energy storage capacitor together with switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       13. In a thruster particularly well adopted to control the attitude of a small space satellite the improvement comprising: 
       (a) a plurality of propellant modules, each module comprising a first and second electrode with spacer material positioned between said first and second electrode, which spacer material can readily vaporize upon the application of a high voltage pulse applied thereto; and  
       (b) a single thruster control means for selectively applying electrical energy stored within a single energy storage capacitor across spacer material of selected ones of said modules.  
     
     
       14. The thruster of claim  13  wherein said spacer material comprises a tetrafluroethylene polymer. 
     
     
       15. The thruster of claim  13  wherein discharge of said energy storage capacitor applies a voltage pulse of at least 1000 volts across said spacer material. 
     
     
       16. The thruster of claim  14  wherein discharge of said energy storage capacitor applies a voltage pulse of at least 1000 volts across said spacer material. 
     
     
       17. The thruster of claim  13  wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       18. The thruster of claim  14  wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       19. The thruster of claim  15  wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       20. The thruster of claim  16  wherein said thruster control means includes switch means for coupling said energy storage capacitor across spacer material of selected propellant modules after charge up of said capacitor. 
     
     
       21. A thruster for a spacecraft comprising, 
       a) spaced coaxial conductors having an inner conductor and an outer shell conductor positioned about said inner conductor, which conductors are separated by propellant spacer material, which material can ablate or vaporize upon application of a high voltage pulse thereto and  
       b) thruster control means for applying said high voltage pulse to said conductors across said propellant spacer material.  
     
     
       22. The thruster of claim  21  wherein said spacer is selected from the group of ablative material, solid material and copolymer material. 
     
     
       23. The thruster of claim  21  wherein commercially available RF coaxial cable is employed as said coaxial conductors. 
     
     
       24. A compact thruster for a spacecraft comprising, 
       a) spaced coaxial spaced conductors having an inner conductor and an outer shell conductor positioned about said inner conductor, which conductors are separated by propellant spacer material, which material can ablate or vaporize upon application of a high voltage pulse applied thereto,  
       b) a first circuit having a first switch electrically connecting said spaced conductors,  
       c) a pulse generating circuit having a power supply connected across a capacitor,  
       d) a pulse discharge circuit having a second switch also connected across said capacitor, said pulse discharge circuit being electrically connected to said first circuit by voltage step-up means, such that upon closing said first switch and then closing said second switch, said capacitor delivers a high voltage pulse through said pulse discharge circuit and across said conductors ablating or vaporizing a portion of said spacer therebetween, generating thrust.